While correcting a CFSP exam, I read a question which went something like this:
If you purchase all IEC 61508 certified equipment for a low demand safety instrumented function, then to meet the requirements of IEC 61511:
A. No other design verification is needed
B.…
Some designs push their operating specifications right up to the limit of the components in the system or device. (let’s not talk about the designs that try to spec a limit that is beyond the capability of one or more components… phooey on them!) And if you make a…
Performing a risk analysis as part of an IEC61508 / 61511 / ISA 84.01 safety lifecycle process can be quite challenging. How can you be sure you get what you need within budget and how can your team provide the best value for money?…
Today, April 15th, is tax-day in the US. Ok, the Internal Revenue Service (IRS) has given us a few extra days this year (the tax filing deadline is not until April 18th).
There are a lot of similarities between how you do your taxes and how you handle…
Imagine. Marketing has just approached the engineering department and says your new safety product must have SIL 3 Capable certification instead of SIL 2 to be successful. You are in the engineering group developing this new product. Now what?
Let’s assume that the “change request” makes…
Imagine: An automobile that has only one window in the front. No side windows. The driver can see to steer the auto forward and turn, but cannot see completely from side to side. What happens when the driver reaches an intersection with no traffic lights? The driver cannot see…
I got a copy of the IEC 61508 certificate for a solenoid valve today from an engineer who thought something was wrong. Although the certificate was from a well known certification company, the certificate gave a “Dangerous Failure Rate” of 1.7 FITS (1.7 * 10-9 failures per…
As safety professionals, it is our duty to attempt to educate and explain to the public. Perhaps the biggest challenge is to explain the concept of risk. Many times after an accident we have heard a politician say something like “We will do whatever it takes to make sure…
I came across an interesting blog post the other day…
Talk about operating blind. A great picture shows the status of the control room in the Fukushima Dai-Ichi Unit 2 reactor…Nothing is working (besides the lights)!
All of the computer monitors are blank. The clock…
Alarm Overload…Nuisance Alarms…Alarm Floods…Incorrectly Prioritized Alarms…. These alarm management problems are all too common in the modern Distributed Control System (DCS).
Why is this? In the “olden” days (read panel boards and alarm lightboxes), there was considerable thought put into what alarms were necessary because there was limited real…
Stuxnet has, rightly, generated a significant amount of discussion and concern with the industrial automation community. Fortunately, unless you operate a uranium enrichment facility using Siemens S7 PLC’s and some very specific variable frequency drives (VFDs) you probably haven’t been directly impacted by the Stuxnet…
I am told that plagiarism is a compliment. Since exida is the leading company for IEC 61508 certifications I suppose it was bound to happen. Well it did. exida got an email from our sales representative in China. He asked why this certificate was not listed on the…
I have often heard the question “Who says they can issue a certification?” This is often accompanied by “Why can’t I certify my own product?” “Who knows our design better than we do?” Good questions.
The IEC 61508 standard does not require certified products for Functional Safety. …